Breaking news into CNN. New evidence that Flight 370 had turned around and was traveling at a low altitude. This coming from the co-pilot's cell phone. It turns out it was on after the transponder stopped working. A U.S. official with first-hand knowledge of the investigation says Malaysia knows this because the phone was searching for service, bouncing off of a cell tower, after the jet lost contact. Coming up, we'll go live to the flight simulator for an explainer on that.

But first, today, a new and critical phase of the search for Flight 370, 39 days after it vanished and a week after the last apparent encounter with pings from the plane's black boxes. The man heading up the search accepted that the batteries are likely dead now and called in the U.S. Navy's underwater drone, the Bluefin.

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ANGUS HOUSTON, JOINT AGENCY COORDINATION CHIEF: The deployment of the autonomous underwater vehicle has the potential to take us a further step towards visual identification since it offers a possible opportunity to detect debris from the aircraft on the ocean floor.

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KEILAR: The Bluefin uses sonar to map a section of the ocean never before explored. But this is just painfully slow here. It takes two hours to even get down there. It takes 16 hours to scour just 15 square miles before heading back to the surface. And the absence of any plane debris on the surface, well that means the visual searches are soon to be called off. This is despite the fact that an oil slick has been spotted, liters of fluid from it, possibly from the plane, now scooped up for testing to see where it came from. The cell phone report adds this other layer of mystery to the question of what happened to Flight 370 and also another clue, but does it bring us any closer to the truth? CNN's Martin Savidge is inside the flight simulator with trainer Mitchell Casado.

I mean, Martin, what do you make of this report?

MARTIN SAVIDGE, CNN CORRESPONDENT: Well, Brianna, up until now we've had two real indicators of what the flight plan might have been for this particular airplane. The one was the Inmarsat intel that was the information that came from those handshakes once every hour. The other was from radar data that the Malaysian government reported to us. So now you've got a third level, which is the cell phone. And apparently the cell phone seems to back up the radar information we've been getting. In other words, that the plane did turn off course and it did seem to -

KEILAR: All right. I'm so sorry to interrupt you, Martin, but we're actually going to go live now to Kansas City, where a press conference is going on. The mother of the 14-year-old who was killed in the shooting at the Jewish community center. Here's her talking to cameras.

MINDY CORPORON, MOTHER & DAUGHTER OF SHOOTING VICTIMS: We didn't want to hide and not let people grieve with us. So that's why we're here. And - so I guess my statement would be very similar. I said I went to a vigil last night impromptu because I heard that students from Reat's school would be there. And he loved school and he loved his friends, so I wanted to be there.

And -- so what happened is, Reat was going to the Jewish Community Center with my dad, who we called Popeye (ph), and Reat named him Popeye and he named my mom Yayyay (ph). And they were going to the Jewish Community Center for Reat to try out for Kansas City Super Star. And Reat's a freshman and you can try out for that program when you're in high school. And he's been wanting to try out for three years. And this is his first time to get to try out.

He's been practicing and he had two songs that he was - might -- thought he might get the chance to sing, too. The first one was "On the Street Where You Live" from "My Fair Lady". He was dressed in a coat and tie and a black shirt and a hat. He was all ready.

And then if they were going to give him a chance to sing again, he was going to sing "You Will Miss Me When I'm Gone." And I was lucky enough to get to hear both of those songs before he left the house. I waited for my dad to pick him up, make sure everything was OK and I had him sing them one more time. And I got to kiss him and tell him I loved him.

And I left for a lacrosse game that got cancelled then due to weather and I left the lacrosse game and headed to the Jewish Community Center. And I didn't have my phone, but at the time I didn't need it. When I pulled into the parking lot, I saw that my dad's truck was there and that the car doors were open and I wondered where my - why my dad wasn't just standing there. And as I pulled up, I saw that he was lying on the ground.

And my first thought was that he had had a heart attack and he was just lying there. But very quickly I realized that it wasn't that and I knew that my dad was in heaven within seconds. And I ran around the truck and I saw my son lying there and there were already two people with him. There were two men, whom I don't know, and they were holding him and I did not get a good look at him. I saw just that he seemed a little lifeless, but I did not get a significant look at him before someone named Nikki (ph), who I'm very blessed for him, grabbed me and held me very tightly and pulled me away from the scene.

And as I went into the Jewish Community Center, I saw that - then I saw bullet holes in the glass. And then it started to dawn on me what had happened. And I want to thank the Jewish Community Center. It was very unreal and no one should have to go through that. But they - you know, they were careful in locking down the location and it was a crime scene and it didn't feel like a crime scene to me. It was my family. I had two family members that were lying on the ground.

So I felt a lot of comfort. I felt God immediately. I prayed that Reat would survive. I prayed and prayed and prayed that he would survive. But I later found out why he didn't. I know that they both died from head trauma and I feel confident from what I heard that they didn't feel anything. They didn't know what was coming. They were ambushed.

So it's going to be really hard. And I wanted to tell people that last night at the vigil. This isn't easy. People keep saying, how come you're so strong? And I'm strong because I have family. I'm strong because I have faith. I know that God did not do this. I know that there are evil, evil actions. But what we do have is each other and we have love and we have prayer and we have friends and family. Our phone is ringing off the hook. People from high school and college and people around the United States and all of you here want to hear what we want to say.

You know, it was a horrible act of violence and my dad, our dad, and my son were at the wrong place at the wrong time for a split second. And we want something good to come out of this. We don't know what that's going to be, so we want people to let us know if they think that something good has come from it.

I talked to the transplant group today. That was not an easy call. And hopefully my son will be a tissue donor, possibly an organ donor. They don't know. He was 14 and he had his permit and he had already signed up to be a donor on his own. And they knew that. And so I answered all the parent questions and so I hope that I hear that he's able to help other people.

He loved debate. He loved to debate.

UNIDENTIFIED MALE: Yes, he did.

CORPORON: He went to seven debate -- seven debate contests last semester. His first semester of his freshman year. And he lettered. He got his letter and he was very proud of that. And he planned on going to debate camp this summer. He made it into "Tom Sawyer" at Theater in the Park this summer. He was going to be in the cast of "Tom Sawyer." So we'll have to go see that. They'll find somebody else for his role. And then he made it into "Starlight Stars" for the summer also. So he was up and coming.

But, you know what, he was with us for a wonderful 14 years. He had a really full life for a 14-year-old. And we were very blessed. And I've heard from his friends and I've talked to his best friend and they love him, too. So I hope that this is helpful to other people in the nation. I hope this is helpful to people who are grieving. You know, you have to reach to God, you have to reach to your friends and search your soul. And that's what it's about. It's about us who are living and it's about loving and caring for one another.

Thank you.

WILL CORPORON, SON & UNCLE OF SHOOTING VICTIMS: You can see who got the strength in the family. My name is Will Corporon. That's my father and my nephew that were killed. And you know everybody wants to know how we're doing. And, to varying degrees, we're muddling through. You know, no one thinks they're going to have funerals to plan. And, you know, no one believes this will happen to you, to your family.

I know that my dad would have given anything if it could have just been him. He'd have stood up and just said, take me, if that would have been offered. And that makes it so much harder.

My father leaves behind a legacy of faith and family and community. He was -- I was just a baby when he was in college and he and my mom worked and put him through medical school. He was in family practice. I've heard from people today, you know, who said, my children, his hands were the first hands on the planet that touched my children. And I am so grateful for that. And it touches my heart to hear things like that. He touched so many. And just leaves a wonderful legacy of family.

We do have a strong family, and boy it's being tested. We don't know why bad things happen to good people. Nobody does. We choose not to focus on the why or what happened or -- it really doesn't matter to us. The fact remains that, you know, two of the people we loved most in our life are now not here with us. And we do take comfort that they were together. And we take comfort that they didn't suffer. And we're very grateful to my parents and my sister and brother, church family and here and community, friends that they have here and all our friends all over the United States that we're hearing from.

I'm happy to take a question or two if you could please just limit it to the family.

UNIDENTIFIED MALE: Do you know what - could your nephew get a chance to sing? Was he -

WILL CORPORON: No. I -- my understanding is - and I've not - I don't know this 100 percent, but my understanding is they literally had just pulled into a parking place and opened the doors to get out. They were ambushed.

UNIDENTIFIED FEMALE: Could you speak to the fact that (INAUDIBLE) what we heard is that your family really would appreciate focusing on the victims (INAUDIBLE) and not anybody else (INAUDIBLE)?

WILL CORPORON: Well, it takes no character to do what was done. It takes no strength of character. It takes no backbone. It takes no morals. It takes no ethics. All it takes is an idiot with a gun. So, there's no need to focus on that. I mean it could have been a - it could have been a - an accident on an icy road. They were together all the time. My father and Reat. And the other grandkids. I mean my dad always had one of them with him, or more. It could have been a drunk driver. It could have been a car accident. It could have been any number of things.

So, for us, again, it's -- the tragedy is that they're not here. The other part will be dealt with by those who are going to deal with it. And really doesn't - you know, that's going to play out.

Our goal is to shine the light on my father and my nephew and hopefully on -- just the senselessness of these kinds of things. It's just - there's no rhyme or reason to it. I mean that idiot - that idiot absolutely knocked a family to its knees for no reason. My dad should be seeing patients today at his work. You know, Reat, if they had school today, would have been in school today studying and being with his friends. There's no reason - no reason for this. And it's just a tragedy.

UNIDENTIFIED MALE: Could you - could you -

UNIDENTIFIED MALE: Can you talk about the work your father - I imagine your father taking his grandson to this tryout. He knew how much he loved watching him act and seeing (INAUDIBLE).

WILL CORPORON: The whole family loved it. Very supportive of Reat. And all the grandkids. Whether it's music or baseball or lacrosse or dance or whatever. Again, family first. I don't just say that. That's not just words. That is fact. That is the life. That is the whole reason they moved here in 2003 up here was to be closer to my sister, my brother, and their kids, to be part of their lives, because that's what they wanted to be. And that - so that's -- he died doing exactly what he wanted. If you could ask him to pick something, if he could, you know, that, you know, probably wouldn't be far off the mark for him to say being with his - doing something with one of his grandkids. Like I said before, he would have, I'm sure, given anything to just - it just be him. And we all feel that way.

UNIDENTIFIED MALE: Can you talk about -

UNIDENTIFIED MALE: Can you tell -

UNIDENTIFIED MALE: (INAUDIBLE) in performing (INAUDIBLE)?

WILL CORPORON: Oh, Reat very much loved that. That was a huge part of his life. It has been since he was little. He's gotten to be in some productions in school and some - and summer productions. All of you have probably seen, he was asked to sing the "Star Spangled Banner" at an event not that long ago. Very important to him. But it wouldn't have mattered if it was singing or if it was any other activity. Whatever they wanted to do is what was important to the family. And that was just what his passion was. He loved singing in the church choir. Loved singing in choir at school. We're a musical family. We do sing a lot and have for years. Holidays and things like that. And so it's just kind of a natural thing for him to be interested in.

Yes, sir.

UNIDENTIFIED MALE: Could you tell me a little bit more about the bond between your father and your nephew? And in particular, what is it that they saw in each other? What connected them?

WILL CORPORON: You know, they did a lot of things together, Reat being -- he's not the oldest grandchild, but he's kind of the oldest of the next - I have the oldest, who's 23. So the next group, he's the oldest. So they spent a lot of time with him when he was younger. Just did a lot of his early scouts with him, camping, things like that. I wouldn't say that his bond with Reat was any more significant necessarily than with any of the other grandkids. It's just that they just happened to be together - be together this day.

Again, I can't emphasize enough, these are active grandparents. And he still worked 40 hours a week. These are active people living an active life and a huge part of that life every day had something to do with grandkids, whether it was Reat or one of the other grandkids.

UNIDENTIFIED MALE: And just tell us a little bit more about - about your father (INAUDIBLE). Where did he move from when he came here? (INAUDIBLE) his practice -

WILL CORPORON: He was practicing - a family practice in Oklahoma from 1976 to 2003. Actually earlier than that, 1972 to 2003. And they moved up to the Pittsburgh/Navada (ph) area for a little while and then up to here. And he was an emergency room physician and then about - I'm going to get this wrong, but about a year ago took a medical director job at an operational health company.

UNIDENTIFIED FEMALE: Now you had said that there's some other children who (INAUDIBLE) had several grandchildren. It's hard enough (INAUDIBLE) to accept something like this happening. How are the children (INAUDIBLE)?

WILL CORPORON: You know, to be really honest, I'm not really sure. I haven't - I haven't got to visit with Reat's brother yet. You know, I know this, kids are resilient. There have been a lot of tears. It's going to be a very hard week for them. You know, and not just, obviously, the brother, not just losing a brother, but a, you know, a beloved grandfather. So it's going to be difficult. It's going to be just - it's just going to be difficult for all of us.

So I just want to wrap things up by saying that my mother and all the family that's in town now and coming into town and those that I've talked to really appreciate you all, the media respecting our privacy, being as forthcoming as we can possibly be. I know that when we have arrangements have been made here with Pastor Hamilton (ph) here at the church, I'm sure those will be - those will be made available. Mindy has two or three charities I know that she would like, and I don't have those with me but I can e-mail them to you, that she would like to get out to have donations made in memory of Reat and my father.

And I just can't stress enough that, you know, we, as a family, have been dealt a huge, huge blow, as I'm sure you can see and perhaps imagine. But we'll go on and we'll get through this and we'll always have a huge holes, two huge holes, that will never be full - never be filled. You know, every day is just going to be a reminder. But we do hope that, you know, if there's any way possible that any little sliver of good, goodness, grace can come of this, that then by the sheer grace of God, it will not have been just totally, totally for nothing.

So, thank you all very much.

KEILAR: Some heartbreak and courage from the Corporon family there in Leawood, Kansas, a suburb of Kansas City. That man, Will Corporon, is the uncle of Reat Underwood, the 14-year-old who was killed at the Jewish Community Center there yesterday, and he is the son of Reat's grandfather, William Lewis Corporon. Trying to bring the focus back to the victims. The Corporon's saying that they're relying very much on faith and family. They're trying to find comfort wherever they can. The fact that the two -- their two loved ones didn't suffer. That they were together at the time. And they said they're not trying to focus on the why because they say it doesn't matter.

And we also heard, Sunny Hostin, as I bring you in, what they called the gunman, Frasier Glenn Cross (ph). We heard Will Corporon there call him an idiot with a gun. He's accused of gunning down these two, as well as someone else, a woman, at a nearby Jewish assisted living facility in Overland Park, Kansas, yesterday. Talk to us, Sunny, about what this means. The U.S. attorney's office said today that it will prosecute the cases as a hate crime. How does that work in terms of jurisdiction, you know, federal, local, and what kind of charges this man may face and would he only be tried once?

SUNNY HOSTIN, CNN LEGAL ANALYST: Sure. You know, it's likely that the federal government is going to take the lead. I mean I think that's the sense, Brianna, that we got from what they said today during the press conference. And that does typically happen. There is sort of attention oftentimes between the federal prosecutor's office and also the state prosecutor's office. But it looks like they've been working together. But the U.S. attorney of Kansas made it very clear that they are going into the grand jury, that they have evidence of a hate crime.

And what that means is this will be prosecuted on the federal level under the Civil Rights Act as a federal hate crime and they have to show, and it seems like they have to pretty strong case, they have to show that the crime here was motivated in whole or in part by the offenders bias against these people. And so we have information now that he is a lifelong white supremacist, was a grand dragon of the Ku Klux Klan. And when you're looking at that as a federal investigator, you do have the makings of a federal hate crime case.

Now, we know that there is a death penalty under federal law and so I'm sure that is something that is going to be looked at, no question about it, because you have three victims here. This seems to me to fall under a first degree premeditated murder based on bias. And the Justice Department is very well versed in those kinds of cases. My sense is that the U.S. attorney's office there will work with the Justice Department in D.C., the civil rights division, in bringing this case. But they are obviously, Brianna, moving extremely quickly because you heard during the press conference today that they had - it's a four witness case. That is a very strong case. Typically when you have a murder case, you do not have that many witnesses. And if you have this history hate, I think that the government has what seems to be a very strong case.

KEILAR: Yes, none of the victims Jewish, as it turns out, but they were at Jewish - a community center, as well as an assisted living facility. And that's really what it comes down to, the intent there.

Sunny Hostin, thank you so much. We really appreciate it.

Now, up next, we'll be back to our breaking news in the search for Flight 370. We'll have more on the co-pilot's cell phone and the signal detected after the plane lost contact. Our experts weigh in. This is CNN's special live coverage.